EP3660174B1 - Verfahren zur rückgewinnung von nd2fe14b-körnern aus massegesinterten nd-fe-b-magneten und/oder magnetabfällen durch elektrochemisches ätzen - Google Patents

Verfahren zur rückgewinnung von nd2fe14b-körnern aus massegesinterten nd-fe-b-magneten und/oder magnetabfällen durch elektrochemisches ätzen Download PDF

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EP3660174B1
EP3660174B1 EP18208508.4A EP18208508A EP3660174B1 EP 3660174 B1 EP3660174 B1 EP 3660174B1 EP 18208508 A EP18208508 A EP 18208508A EP 3660174 B1 EP3660174 B1 EP 3660174B1
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magnets
magnet
grains
recycling
recovery
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EP3660174A1 (de
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Xuan XU
Saso Sturm
Kristina Zuzek Rozman
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Jožef Stefan Institute
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Jožef Stefan Institute
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Priority to US16/687,749 priority patent/US11232902B2/en
Priority to JP2019213434A priority patent/JP2020084331A/ja
Priority to CN201911180249.4A priority patent/CN111223657B/zh
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B59/00—Obtaining rare earth metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
    • C22B7/006—Wet processes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
    • C25C5/02—Electrolytic production, recovery or refining of metal powders or porous metal masses from solutions
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F3/00—Electrolytic etching or polishing
    • C25F3/02—Etching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a method for recovery of Nd 2 Fe 14 B grains from bulk sintered Nd-Fe-B magnets and/or magnet scraps.
  • Neodymium iron boron (Nd-Fe-B) magnets are widely used in many applications such as hard disk drives, wind turbines, industrial motors, acoustic transducers and electric vehicles due to their high energy density [1]. Since they incorporate 20-30 wt% of rare earth elements (REEs) that include mainly Nd with small addition of Dy and/or Tb, they represent an important secondary REEs resource [2]. In 2014, 22% of rare-earth oxides (REOs) were consumed for the production of Nd-Fe-B magnets globally which makes them one of the largest applications among all REEs [3]. The demand for REEs was estimated to grow by >8% per annum until 2020 [4].
  • REEs rare earth elements
  • the oxide could not be extracted out, beacause of which grain boundary modification is required by adding REE metals or REEs-containing alloys [13, 19].
  • the pyrometallurgical routes can be used to remelt the REE alloys and extract the different REE in the form of oxide, halide, fluoride or other metallic compound which can then be reduced to metallic form [20-25].
  • these pyrometallurgical processes operate at a temperature of around 750-950 °C and are thus energy intensive.
  • Hydrometallurgical recycling processes designed for Nd-Fe-B magnets are promising due to the mild operating temperature, relatively simple equipment and the continuous separation ability [4, 9]. In hydrometallurgical processes, however, Nd-Fe-B magnets are completely dissolved with an acid.
  • the roasting pretreatment at 900 °C is generally required.
  • Iron which is the major component of Nd-Fe-B magnets (60-70%) consumes large amount of acid, alkali and other precipitation agents that cannot be recycled in the whole process [8, 9].
  • REEs are concentrated by solvent extraction and then are precipitated with either oxalic or carbonic acid. The precipitate is further calcined at 950 °C to form REOs, which can then be returned to the initial manufacturing process for Nd-Fe-B magnets [26].
  • the magnet-REEs-magnet recycling requires large amounts of chemicals and considerable energy with harmful emissions to the environment.
  • sintered Nd-Fe-B magnets contain 87 ⁇ 92% Nd 2 Fe 14 B phase which is barely oxidized due to the protection of the grain boundary (typically Nd-rich phase) [18, 27]. Therefore, in stead of recovering REEs from the end-of-life Nd-Fe-B magnets or magnet scraps, direct recovery of the Nd 2 Fe 14 B phase for fresh NdFeB magnets making would dramatically reduce the chemical usage and energy consumption.
  • a facile, energy efficient and environmentally friendly route for recovery of the Nd 2 Fe 14 B phase is yet to be presented.
  • Nd-Fe-B magnets have been investigated worldwide.
  • One of these approaches is to bulk-recycle all the materials in an Nd-Fe-B magnet without separation. This has been termed "magnet-to-magnet recycling".
  • VCMs voice coil motors
  • the powder was aligned, pressed and resintered and this procedure was repeated four times with a progressive fall in the density (7.56-6.70 g cm -3 ) and in the magnetic properties (remanence: 1180-1053 mT, coercivity: 870-343 kA m -1 ).
  • Nd-FeB magnets Extraction of all the REEs from NdFeB magnets for new magnet production is an alternative way for recycling. This could be termed "magnet-REEs-magnet recycling".
  • High-temperature processing of Nd-Fe-B magnet is to selectively convert REEs in the magnet into another phase (i.e., from metallic RE to RE chlorides) which separates the main non-REE components.
  • the separated REEs in the other phase can be used for RE metal production through molten salt electrolysis or metallothermic reduction.
  • Nd-Fe-B magnet scrap can be selectively extracted using molten MgCl 2 -KCl salts at temperatures of 600-1200 °C.
  • Nd-Fe-B magnet generally operates at a temperature of around 750-950 °C and is thus energy intensive.
  • Hydrometallurgical recycling processes operated at a mild temperature to recover REEs are alternative methods for Nd-Fe-B magnets recycling.
  • Nd-Fe-B magnet scraps are milled with/without roasting (annealing in air).
  • the obtianed powders are completely dissolved in concentrated HCl/H 2 SO 4 solutions.
  • REEs can be precipitated from leach solutions by adding oxalic acid or hydrogen fluoride to form oxides or fluorides.
  • the recovery of REEs can reach over 90%. [ Bandara, H.D., K.D. Field, and M.H.
  • the "magnet-to-magnet recycling" of Nd-Fe-B magnets leaves the REOs phase to stay in the grain boundary without any seperation, higher REOs content with the repeated recycling could not be avoided which significantly degrades the magnetic properties.
  • the addition of extra extra REE metals/alloys would results in higher cost for recycled magnets making. While the proposed "magnet-REEs-magnet recycling" of Nd-Fe-B magnets requires either high energy input or multiple process steps with consumption of large amount of chemicals which generates large amount of waste and effluents.
  • Nd 2 Fe 14 B grains are recovered from bulk sintered Nd-Fe-B magnets and/or magnet scraps.
  • the Nd-Fe-B magnets are typically magnet scraps, but the method is not limited to magnet scraps.
  • the EOF Nd-Fe-B magnets contain up to 90% alloy phases which are suitable for electrochemical recycling.
  • Nd-Fe-B magnet scraps are arising from cutting block magnets into shape or off-quality magnets, which can be suitable as an input for direct recycling processes (e.g. remelting).
  • the wet swarf from magnet finishing processes is only suitable for indirect recycling processes, since the material is contaminated and partly oxidized.
  • the Nd 2 Fe 14 B grains are recovered by electrochemical etching of the bulk sintered Nd-Fe-B magnets or magnet scraps using an anodic oxidation process.
  • the metallic Nd-rich phase (Nd(0)) in the grain boundaries is oxidized to Nd 3+ as ions on the anode.
  • the liquid electrolyte used in this process is formed of a non-aqueous solvent in order to prevent the Nd 2 Fe 14 B grains from oxidation. This allows direct reuse of the collected Nd 2 Fe 14 B grains for new magnet making.
  • the grain boundaries of the Nd-Fe-B magnets and/or magnet scraps contain metallic Nd and Nd-oxides (NdO x ) [28, 29].
  • the metallic Nd in the Nd-rich grain boundary phase is preferencially etched / oxidized and dissolved in the non-aqueous solvent. Due to this anodic oxidation the Nd 2 Fe 14 B grains in the Nd-Fe-B magnets and/or magnet scraps are released. The released magnetic Nd 2 Fe 14 B grains are then collected by using an external magnetic field gradient, provided via e.g., commercial Nd-Fe-B magnet.
  • the non-magnetic particles that mainly consist of Nd-rich metal and oxides are preferably recovered by filtration.
  • the dissolved Nd-rich phase in the electrolyte can be further separated and recovered in the form of REOs, the technique of which has been well known publically.
  • the applications of interest include the recovery of Nd 2 Fe 14 B grains ready for new magnet making and recovery of REEs ready for RE metal production by a facile, energy efficient and environmentally friendly route.
  • the electrochemical etching of the Nd-Fe-B magnets and/or magnet scraps is performed in a three-electrode cell - having an anode, a cathode and a reference electrode - where one or several scrapped or EOL bulk sintered Nd-Fe-B magnets (after the coating is removed) serve(s) as the anode, preferably a Cu foil is used as the cahtode and a Pt wire is applied as the reference electrode.
  • dehydrated FeCl 2 (to improve the electrolyte conductivity) is dissolved in the liquid electrolyte, e.g. in dimethylformamide (DMF) as the electrolyte.
  • DMF dimethylformamide
  • the Nd 2 Fe 14 B grains can be collected on the anodic part magnetically by a Nd-Fe-B magnet after applying the anodic current density (2 ⁇ 48 mA ⁇ cm -2 ).
  • a conductive netting mesh which is commonly used in the industry can be used together with the collected end-of-life bulk magnets or the magnet scraps to form the anode.
  • Such a netting mesh typically holds around 10 kg Nd-Fe-B magnets.
  • This proposed anodic etching process of Nd-Fe-B magnets is acid-free and operating at room temperature. Generally, the temperatures can range from 0 °C to about 90 °C.
  • the Fe deposition occurs with a high current efficiency, due to the application of a non-aqueous solvent (e.g. DMF).
  • a non-aqueous solvent e.g. DMF.
  • the collected Nd 2 Fe 14 B grains are not oxidized and are ready for a direct new magnet production.
  • the obtained metallic Fe on the cathode coming from electrodeposition can be used as a raw material for different applications.
  • Nd 2 Fe 14 B grains are recovered from an EOF Nd-Fe-B magnet using dimethylformamide as the liquid electrolyte.
  • Dimethylformamide (DMF, >99%) was purchased from Sigma-Aldrich, Germany. Prior to using, molecular sieves (4A, Sigma-Aldrich, China) which were dried under vacuum at 160 °C for more than 24 hours was added into DMF to remove the water. FeCl 2 ⁇ 4H 2 O (>99.99%, Sigma-Aldrich) were dehydrated under vacuum at 140 °C for 24 hours. All dried chemicals were stored inside a closed bottle in an argon filled glove box with water and oxygen content below 1 ppm. The water concentration which was determined by Karl Fischer titration (C20S, Mettler-Toledo, Switzerland) in the electrolyte was less than 50 ppm.
  • the sintered bulk Nd-Fe-B magnet waste (chemical composition: 66.34 wt.% Fe, 22.10 wt.% Nd, 5.78 wt.% Dy, 5.78 wt.% other elements) used in this example was supplied by Magneti Ljubljana d.d (Ljubljana, Slovenia). Prior to experiment, these bulk magnets were thermally demagnetized and mechanically polished to remove the coating.
  • an electrochemical cell usable in the proposed method compromises the Nd-Fe-B magnet scrap 1 (15 mm* 30 mm* 2 mm) the coating of which was removed prior processing as the anode, a metallic substrate 2 (10 mm* 10 mm) as the cathode and e.g. a Pt wire 3 (0.5 mm diameter) as the reference electrode.
  • the electrodes were attached to the electrical conductors 4 for connection to electrical instrumentation power supply (not shown).
  • the cathode as shown can be a substrate material such as copper in the form of foil or plate.
  • the electrolyte 5 that surrounds the three electrodes must be a non-aqueous solvent.
  • Nd 2 Fe 14 B grains that fall out of the Nd-Fe-B magnet 1 forming the anode after the Nd-rich grain boundary phase is etched away electrochemically, collected by an external (commercial Nd-Fe-B) magnet 8.
  • the non-magnetic particles 7 that fell out of the Nd-Fe-B magnet 1 forming the anode together with Nd 2 Fe 14 B grains 6 are Nd-based oxides.
  • the proposed method is performed in this example using the three-electrode cell of Figure 1 with 15 mL DMF containing 0.3 M FeCl 2 at room temperature.
  • a Nd-Fe-B magnet (15 mm*30 mm*2 mm) is served as the anode, a Cu foil (10 mm* 10 mm) is used as the cahtode and a Pt wire (0.5 mm diameter) is applied as the reference electrode.
  • Electrochemical etching of the Nd-Fe-B magnet started by applying the current density of 2-48 mA ⁇ cm -2 on the anode. The morphology of the anode was examined by SEM.
  • the initial sintered bulk Nd-Fe-B magnet ( Figure 2a (BEI SEM)) consists of Nd 2 Fe 14 B matrix phase (grey) with the grains size of -10 ⁇ m, Nd 2 Fe 4 B x phase found in triple pockets (light grey), together with Nd 2 O 3 phase (white). On the grain boundaries the Nd-rich (Nd-Fe) grain boundary phase (bright phase) is present, however the analysis with the SEM is not reliable in our case.
  • Nd-rich the structure of which most probably consists of ⁇ -Nd (fcc) and a mixture of different Nd-based oxides (dhcp-Nd 2 O 3 , fcc-NdO, complex-Nd 2 O 3 and h-Nd 2 O 3 ) [29].
  • Figure 2b shows a representative microstructure of the Nd-Fe-B magnet surface after electrochemical etching at 2 mA ⁇ cm -2 for 15 min under room temperature.
  • the measured grain size of the grey phase varies from 5 and 10 ⁇ m, which is consistent to the initial grain size of Nd 2 Fe 14 B matrix phase in the pristine as-sintered magnet. Some pores / holes observed in each grey phase are possibly due to the etching of Nd-rich phase inside the grains. Based on the obtained results, 67.2% of Nd-Fe-B magnet were recovered in the form of the Nd 2 Fe 14 B grains.
  • Figure 2d (BEI SEM) shows that the filtered particles are either the Nd-oxide phases (round particles) and Nd-based oxides and alloy phases (elongated ribbed particles), that resulted from the anodic etching of Nd-based alloy during electrolysis.
  • An XRD pattern of the magnetic powders mainly shows reflections characteristic of Nd 2 Fe 14 B phase (Reference PDF: 04-005-2711) ( Figure 3 ) which indicates that the grey phase in both Figure 2b and c is Nd 2 Fe 14 B phase.
  • the etched Nd-rich phase which was dissolved in DMF after filtration was measured by ICP-MS (Inductively Coupled Plasma - Mass Spectrometry) (see Figure 4 ).
  • the etching rate of Nd 3+ and Dy 3+ were calculated as 2.3668 and 0.685 mg L -1 min -1 , respectively.

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Claims (10)

  1. Verfahren zur Gewinnung von Nd2Fe14B-Körnern aus gesinterten Schütt-Nd-Fe-B-Magneten und/oder Magnetschrott, bei dem die Nd-Fe-B-Magnete (1) und/oder Magnetschrott unter Verwendung eines nicht-wässrigen Flüssigelektrolyten anodisch oxidiert werden, wobei die anodische Oxidation die Nd2Fe14B-Körner (6) in den Nd-Fe-B-Magneten (1) und/oder Magnetschrott freigibt, wobei die freigesetzten Nd2Fe14B-Körner (6) während und/oder nach der anodischen Oxidation magnetisch gesammelt werden.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die anodische Oxidation in einer Dreielektroden-elektrochemischen Zelle mit einer Anode zumindest teilweise aus den Nd-Fe-B-Magneten (1) und/oder Magnetschrott, einer Kathode und einer Referenzelektrode durchgeführt wird.
  3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, dass die Kathode aus einem Cu-Substrat (2) und die Referenzelektrode aus einem Pt-Material (3) gebildet ist.
  4. Verfahren nach einem oder mehreren der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass als flüssiger Elektrolyt (5) ein nichtwässriges Lösungsmittel verwendet wird, in dem sich geätzte Nd-reiche Phasen der Nd-Fe-B-Magnete (1) und/oder Magnetschrott lösen.
  5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, dass die in dem Flüssigelektrolyten (5) gelösten Nd-reichen Phasen auch durch Abtrennen der Nd-reichen Phasen vom Elektrolyten (5), insbesondere durch Filtration, gewonnen werden.
  6. Verfahren nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass als flüssiger Elektrolyt (5) Dimethylformamid verwendet wird.
  7. Verfahren nach einem oder mehreren der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass dem flüssigen Elektrolyten (5) eine Additivverbindung zugesetzt wird, um die elektrische Leitfähigkeit des Elektrolyten zu erhöhen.
  8. Verfahren nach Anspruch 7, dadurch gekennzeichnet, dass als Additivverbindung 0,05-0,3 Mol L-1 FeCl2 zugegeben werden.
  9. Verfahren nach einem oder mehreren der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass Nd2Fe14B-Körner (6) im Größenbereich von 5 bis 10 µm magnetisch gesammelt werden.
  10. Verfahren nach einem oder mehreren der Ansprüche 1 bis 9, dadurch gekennzeichnet, dass die anodische Oxidation bei einer Temperatur im Bereich zwischen 0°C und etwa 90°C durchgeführt wird.
EP18208508.4A 2018-11-27 2018-11-27 Verfahren zur rückgewinnung von nd2fe14b-körnern aus massegesinterten nd-fe-b-magneten und/oder magnetabfällen durch elektrochemisches ätzen Active EP3660174B1 (de)

Priority Applications (5)

Application Number Priority Date Filing Date Title
SI201830466T SI3660174T1 (sl) 2018-11-27 2018-11-27 Postopek za ponovno pridobivanje zrn ND2FE14B iz gmote sintranih ND-FE-B magnetov in/ali magnetnih odpadkov z elektrokemijskim jedkanjem
EP18208508.4A EP3660174B1 (de) 2018-11-27 2018-11-27 Verfahren zur rückgewinnung von nd2fe14b-körnern aus massegesinterten nd-fe-b-magneten und/oder magnetabfällen durch elektrochemisches ätzen
US16/687,749 US11232902B2 (en) 2018-11-27 2019-11-19 Method for recovery of Nd2Fe14B grains from bulk sintered Nd—Fe—B magnets and/or magnet scraps by electrochemical etching
JP2019213434A JP2020084331A (ja) 2018-11-27 2019-11-26 電気化学エッチングによってバルク焼結Ｎｄ−Ｆｅ−Ｂ磁石及び／又は磁石スクラップからＮｄ２Ｆｅ１４Ｂ粒を回収する方法
CN201911180249.4A CN111223657B (zh) 2018-11-27 2019-11-27 通过电化学蚀刻从块状烧结Nd-Fe-B磁体和/或磁体废料回收Nd2Fe14B晶粒的方法

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EP18208508.4A EP3660174B1 (de) 2018-11-27 2018-11-27 Verfahren zur rückgewinnung von nd2fe14b-körnern aus massegesinterten nd-fe-b-magneten und/oder magnetabfällen durch elektrochemisches ätzen

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US20230332319A1 (en) * 2022-04-18 2023-10-19 Battelle Memorial Institute Selective recovery of rare earth elements from alloys by electrochemical leaching and electrodeposition

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US5362459A (en) * 1993-05-17 1994-11-08 Pure-Etch Co. Neodymium recovery process
JP2000030919A (ja) * 1998-07-09 2000-01-28 Sumitomo Metal Mining Co Ltd Ｒ−Ｆｅ−Ｂ系磁石用原料粉末の製造方法
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CN104480475A (zh) * 2014-11-04 2015-04-01 烟台首钢磁性材料股份有限公司 钕铁硼磁体表面硬质铝膜层的制备方法
CN104690270B (zh) * 2015-03-08 2016-11-09 北京工业大学 一种利用烧结钕铁硼油泥废料制备高性能烧结钕铁硼磁体的短流程方法
CN107268031B (zh) * 2016-03-31 2019-06-07 蔚山大学产学合作部 重稀土类金属的电化学回收方法
FR3054145B1 (fr) * 2016-07-21 2018-08-31 Centre Nat Rech Scient Procede et systeme pour recuperer des grains magnetiques d'aimants frittes ou de plasto-aimants
CN106319575B (zh) * 2016-11-02 2018-04-17 江西理工大学 一种钕铁硼油泥废料电解制备钕铁硼合金的方法

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JP2020084331A (ja) 2020-06-04
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US11232902B2 (en) 2022-01-25
CN111223657B (zh) 2023-07-21
EP3660174A1 (de) 2020-06-03

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